UNIVERSITY    OF    CALIFORNIA      AGRICULTURAL  EXPERIMENT  STATION 
COLLEGE    OF    AGRICULTURE  8ENJ    'DE  WHEELE«"  '««■««« 

THOMAS     FORSYTH     HUNT,     DEAN    AND    DIRECTOR 

BERKELEY  h.   c.  van  norman,  vice-director  and   dean 

University    Farm  School 


CIRCULAR  No.  168 
September,   1917 

SPRAYING  FOR  THE  CONTROL  OF  WILD 

MORNING-GLORY  WITHIN 

THE  FOG  BELT 

By  Geo.  P.  Gray 


A  comprehensive  series  of  experiments  on  the  control  of  weeds 
by  means  of  chemicals  has  been  carried  on  since  the  fall  of  1915. 
While  the  experiments  are  still  in  progress,  the  results  so  far  reached 
warrant  the  following  recommendations  for  the  control  of  wild 
morning-glory.1 

The  remarkable  potency  of  arsenic  in  destroying  the  roots  of  wild 
morning-glory  when  the  chemical  is  applied  in  small  quantities  to 
the  leaves  and  stems  of  the  plant,  is  the  most  important  fact  thus  far 
determined  in  the  investigation.  This  was  first  observed  at  Center- 
ville  and  later  in  Ventura  County  in  the  fall  of  1915,  but  not  again 
until  the  late  summer  and  fall  of  1916.  The  destruction  of  the  roots 
in  this  manner  takes  place  only  under  restricted  conditions,  however. 
The  main  factors  influencing  the  results  appear  to  be  the  condition 
of  the  plants  and  the  weather.  Thus  far,  no  way  has  been  found 
to  make  practical  use  of  this  fact  except  in  the  coast  regions.  Only 
one  set  of  experiments  was  made  in  a  semi-arid  climate  (Davis). 
There  the  results  were  mostly  negative,  so  that  as  yet  the  procedure 
is  not  recommended  for  climates  away  from  the  coast. 

The  effectiveness  of  a  dilute  arsenical  spray  for  the  control  of 
California's  most  troublesome  weed  on  agricultural  land  within  the 
fog  belt,  without  injury  to  the  soil,  appears  to  have  been  established. 
This  statement  is  based  upon  the  repetition  of  predicted  results  at 
Centerville  on  scheduled  time,  and  the  accumulation  of  confirmative 
data  through  the  experiments  at  Spreckels  and  at  Berkeley. 


i  A  report  of  progress  in  the  investigations  will  be  published  later  as  a  Station 
bulletin.  ,  This  will  contain  a  full  account  of  the  experiments  and,  as  soon  as 
issued,  may  be  obtained  upon  application  to  the  Director. 


PREPARATION   OF  THE   SPRAY 

Arsenic  trioxide  (the  "white  arsenic"  of  commerce)  is  the  basis 
of  the  spray  and  is  used  as  the  unit  in  comparing  concentrations. 
This  is  not  sufficiently  soluble  in  water  for  use  as  an  herbicide  to  the 
best  advantage.  It  is  customary  to  combine  it  with  sal  soda,  soda- 
ash,  caustic  soda,  or  concentrated  lye,  with  which  it  forms  compounds 
readily  soluble  in  water.  The  following  table  may  be  of  use  in 
indicating  the  approximate  weights  of  common  solvents  for  arsenic 
trioxide : 

Arsenic 
Solvent,  trioxide, 

parts  parts 

Sal  Soda  or  Washing  Soda  (Na2CO3.10  H20)    (crystalized  sodium 

carbonate)    2  1 

Soda-ash   (crude  sodium  carbonate),  anhydrous 1  1 

Caustic  Soda   (NaOH)    (sodium  hydroxide)  1  2* 

Concentrated  Lye  (mixture  of  NaOH  and  Na2C02)  1  2 

*  A  soluble  arsenical  can  also  be  made  by  using  one  part  of  caustic  soda  to  four 
parts  of  arsenic  trioxide.  Such  a  solution,  however,  has  a  tendency  to  separate 
crystals  on  standing. 

If  sal  soda  or  soda-ash  is  used,  it  is  necessary  to  boil  the  mixture 
fifteen  or  twenty  minutes  before  the  arsenic  is  dissolved.  If  caustic 
soda  is  used,  little  or  no  boiling  is  required.  In  either  case,  however, 
a  corrosive  chemical  is  formed,  known  as  sodium  arsenite  (or  arsenite 
of  soda),  which  is  readily  soluble  in  water  and  is  even  more  poisonous 
than  the  original  arsenic  trioxide. 

Sodium  arsenite  may  be  purchased  ready-made  as  a  white  powder. 
There  are  also  on  the  market  a  number  of  "weed-killers"  which 
are  concentrated  solutions  of  sodium  arsenite.  Neither  the  sodium 
arsenite  nor  the  commercial  "weed-killers"  can  be  depended  on  as 
having  a  uniform  amount  of  arsenic.  The  "white  arsenic"  of  com- 
merce, however,  can  be  readily  purchased  of  95  to  99  per  cent  purity, 
according  to  many  analyses  made  by  the  Insecticides  and  Fungicide 
Laboratory.  It  is  therefore  recommended  that  a  stock  solution  of 
sodium  arsenite  be  made  up  with  arsenic  trioxide  according  to  the 
directions  below,  or  that  the  purchaser  insist  on  the  dealer's  giving  a 
definite  guarantee  of  the  arsenic  content  of  sodium  arsenite  or  of 
any  prepared  arsenical  "weed-killer."  The  handling  of  arsenic  and 
corrosive  substances  by  one  unfamiliar  with  the  behavior  of  chemicals 
and  the  bringing  of  poisons  into  the  kitchen  are  practices  to  be 
avoided.  The  preparation  of  small  quantities  is  troublesome  and  the 
saving  usually  does  not  warrant  giving  the  necessary  time  and  atten- 
tion. 


3 

The  Stock  Solution. — The  preparation  of  the  poison  presents  no 
great  difficulties  or  dangers  if  adequate  facilities  are  available  out  of 
doors  and  the  operator  is  at  all  familiar  with  the  handling  of  chem- 
icals. If  a  considerable  amount  is  to  be  prepared  the  saving  will  be 
quite  material.  Extra  precautions,  however,  should  be  observed  at  all 
times  in  the  manipulation  of  arsenic. 

Caustic  soda  (sodium  hydroxide),  or  a  good  grade  of  concentrated 
lye,  is  much  more  active  in  dissolving  arsenic  than  either  sal  soda  or 
soda-ash  and  much  less  is  required,  although  the  cost  per  pound  is 
greater.  Very  little  heat  is  required  in  the  preparation  of  sodium 
arsenite  by  means  of  these  materials.  If  made  in  large  quantities 
(five  gallons  or  more)  the  use  of  heat  is  unnecessary.  The  following 
formula  for  the  preparation  of  the  stock  solution  is  preferred  on 
account  of  its  simplicity: 

Granulated  Caustic  Soda  (98  per  cent)  10  pounds 

White  Arsenic  (arsenic  trioxide,  99  per  cent)  20  pounds 

Water,  to  make 5  gallons 

The  solution  may  be  made  as  follows :  Dissolve  the  caustic  soda 
in  about  two  gallons  of  water  in  a  metal  or  wooden  vessel  (preferably 
iron)  and  while  still  hot,  add  the  dry  arsenic,  about  a  pound  at  a  time, 
at  a  sufficient  rate  so  that  the  solution  is  just  at  the  point  of  boiling, 
but  does  not  actually  boil.  Stir  continuously  during  the  addition  of 
the  arsenic  and  until  all  is  dissolved.  Considerable  heat  is  produced 
by  dissolving  the  caustic  soda.  Additional  heat  is  furnished  by  the 
chemical  reaction  involved  in  the  union  of  the  caustic  soda  with  the 
arsenic  to  form  sodium  arsenite.  After  all  the  arsenic  is  dissolved, 
let  the  solution  cool  and  add  water  to  make  exactly  five  gallons. 

Caution. — Do  not  add  cold  water  to  the  hot  solution.  An  ex- 
plosion may  result  as  the  solution  is  hotter  than  the  boiling  point  of 
water. 

If,  for  any  reason,  the  arsenic  fails  to  dissolve  without  the  use 
of  heat,  a  solution  can  be  made  by  warming  the  mixture,  unless  the 
materials  are  of  low  grade.  If  hard  water  is  used  there  will  be  some 
insoluble  matter  in  suspension,  but  it  may  be  disregarded  unless  pres- 
ent in  large  amount. 

The  above  makes  a  convenient  stock  solution  for  diluting  to  any 
desired  strength ;  that  is,  each  gallon  contains  four  pounds  of  arsenic 
trioxide;  a  quart,  one  pound;  each  fluid  ounce  contains  one-half 
ounce  of  arsenic  trioxide. 

The  above  formula  is  preferred,  although  other  formulas  may  be 


made  use  of  by  making  calculations  on  the  basis  of  their  content  of 
arsenic  trioxide.  It  is  inadvisable  to  use  sodium  arsenite  as  the  basis 
of  calculations  on  account  of  the  variation  in  the  active  constituent, 
arsenic.  Strictly  speaking,  elementary  arsenic  should  be  used  as  the 
unit  of  comparison,  but  as  the  trioxide  is  used  as  the  raw  material, 
it  is  permissible  and  more  convenient  to  use  the  latter  as  a  unit. 

The  cost  of  materials  for  the  preparation  of  the  stock  solution  is 
about  fifty  cents  per  gallon  when  arsenic  sells  at  eight  cents,  and 
caustic  soda  at  ten  cents  per  pound.  The  price  of  arsenic  has  recently 
advanced  to  twenty-three  cents  per  pound  and  caustic  soda  has  also 
advanced.  A  revision  of  prices  does  not  seem  warranted  at  the  pres- 
ent time  in  view  of  the  unsettled  market  conditions. 

Diluting  the  Stock  Solution. — The  spray  recommended  for  use 
against  the  wild  morning-glory  is  made  up  by  diluting  the  stock 
solution  at  the  rate  of  one  gallon  to  one  hundred  gallons  of  water.  A 
solution  of  approximately  the  same  concentration  can  be  made  up  for 
small  operations  by  diluting  four  fluid  ounces  (one-fourth  pint)  of 
the  stock  solution  with  three  gallons  of  water.  The  sprays  should  be 
well  stirred  to  insure  uniform  distribution  of  the  poison.  The  con- 
centration of  this  spray  is  equivalent  to  four  pounds  of  arsenic  tri- 
oxide per  hundred  gallons.  Much  weaker  sprays  than  the  above 
proved  to  be  ineffective;  stronger  concentrations  did  not  appear  to 
be  more  effective,  and  possibly  less.  The  stronger  sprays  in  some 
instances  seemed  to  collapse  the  tissues  of  the  vines  and  stop  the 
circulation  of  the  sap  before  the  poison  had  its  full  effect  on  the  roots. 

When  to  Spray. — October  has  been  tentatively  selected  as  the  best 
month  to  spray  for  the  wild  morning-glory.  The  plants  are  more 
apt  to  be  in  the  proper  condition  to  receive  the  spray  at  that  time 
and  the  killing  frosts  do  not  usually  occur  until  later.  The  spray 
may  be  applied  in  November  or  possibly  later  if  the  vines  have  not 
been  killed  by  the  frosts. 

Anyone  contemplating  using  the  spray  in  October  or  November 
should  let  the  vines  grow  undisturbed  after  July  or  August,  as  the 
vines  must  be  at  least  three  or  four  months  old  before  the  spray  will 
affect  their  roots.  A  luxuriant  growth  of  vines  (that  is,  a  large 
absorbing  surface)  is  favorable  to  the  destruction  of  the  roots.  Damp, 
cloudy,  or  foggy  weather  is  also  favorable. 

Application  of  the  Spray. — Two  types  of  hand  sprayers  were  used 
in  the  experiments  without  preference :  one  commonly  called  a  bucket 
spray  pump,  and  the  other  a  pressure  sprayer.  Any  type  of  sprayer 
Hi  towing  a  fairly- fine  spray  may  be  used  for  operations  on  a  small 
scale      A  power  sprayer  would  be  desirable  for  large  undertakings. 


The  spray  should  be  applied  to  the  vines  in  sufficient  quantity  to 
thoroughly  moisten  them,  but  not  to  drench  them.  No  good  can  be 
accomplished  by  allowing  any  of  the  spray  to  fall  on  the  soil.  The 
quantity  of  spray  required  will  vary  according  to  the  density  of  the 
infestation.  A  heavy  infestation  will  require  about  three  gallons  of 
spray  per  fifty  yards,  or  three  hundred  gallons  per  acre. 

Possibilities  and  Limitations  of  the  Method. — The  experiments 
have  shown  that  even  as  many  as  six  successive  applications  of  the 
spray  described  above  produced  no  injurious  effect  on  the  soil.  The 
foliage  of  all  plants,  however,  is  severely  injured  by  the  spray.  The 
application  of  the  method  is  therefore  limited  to  cases  in  which  the 
spray  can  be  applied  to  the  morning-glory  without  coming  in  contact 
with  the  foliage  of  crops.  The  treatment  can  be  given  on  infested 
land  which  is  utilized  for  the  growing  of  any  annual  crop  which  is 
harvested  by  July  or  August.  The  spray  can  be  used  in  orchards  or 
vineyards  if  care  is  exercised  to  prevent  it  from  reaching  the  trees 
or  vines. 

The  method  described  can  not  as  yet  be  said  to  be  one  of  eradi- 
cation. It  has  been  demonstrated,  however,  that  85  to  90  per  cent,  of 
the  morning-glory  roots  on  the  plots  near  the  coast  can  be  killed  to 
a  depth  of  four  feet  or  more  by  the  application  of  a  properly-timed 
spray  to  mature  vines.  New  sprouts  will  emerge  from  the  stubs  of 
the  partially  killed  roots  and  will  eventually  reach  the  surface  and 
produce  new  vines.  Under  these  conditions  they  are  very  puny,  the 
leaves  being  only  about  one-fourth  of  the  normal  size  and  of  a  sickly 
yellowish  color.  The  new  growth  is  quite  different  from  the  normal 
trailing  vine.  When  the  new  shoot  reaches  the  surface,  a  thick  clump 
of  erect  branches  is  produced  not  more  than  eight  or  nine  inches  in 
length.  The  majority  of  the  new  shoots  consume  from  seven  months 
to  one  year  in  reaching  the  surface  so  that  a  crop  can  be  well  estab- 
lished on  the  land  or  an  early  crop  harvested  without  serious  inter- 
ference from  the  weed. 

The  abnormal  condition  of  the  vines  originating  from  the  stubs  of 
the  partially  destroyed  roots  and  the  enfeebled  condition  of  these  root 
stubs,  lead  one  to  believe  that  an  annual  fall  spraying  may  eventually 
eradicate  the  weed.  At  any  rate,  the  cost  of  the  materials  for  the 
spray  treatment  does  not  exceed  $1.50  per  acre  in  normal  times,  nor 
$5.00  per  acre  at  "war  prices,"  and  is  therefore  practicable  as  a 
control  measure. 

While  the  root  systems  of  wild  morning-glory  can  be  destroyed  to 
the  extent  and  under  the  restricted  conditions  previously  discussed, 


6 

the  vines  may  be  easily  destroyed  and  prevented  from  maturing  seeds 
by  the  application  of  the  arsenical  spray  at  any  time  of  the  year.  The 
destruction  of  the  vines  in  this  manner  has  taken  place  in  both  the 
dry  and  the  somewhat  humid  climates  in  which  the  experiments  were 
made. 

DANGER    IN    USING   ARSENIC 

The  writer  is  fully  aware  of  the  danger  connected  with  the  use  of 
arsenic.  For  this  reason,  a  definite  effort  is  being  made  to  find  some 
less  poisonous  herbicide  which  may  be  recommended  for  the  control 
of  weeds.  Thus  far,  however,  no  substance  has  been  found  to  compare 
at  all  favorably  with  arsenic  as  a  plant  poison  when  the  cost  is  taken 
into  consideration.  If  this  powerful  agent  of  destruction  is  to  be 
employed  as  a  tool  for  the  control  of  weeds,  the  user  must  always 
be  alert  to  the  fact  that  it  is  a  destroyer  of  both  animal  and  plant  life, 
the  harmful  and  beneficial  alike. 

Harmless  Appearance. — Most  arsenicals,  when  dissolved  in  water, 
make  colorless  and  odorless  solutions  having  only  a  slight  taste. 
This  harmless  appearance  greatly  adds  to  the  danger  of  accidental 
poisoning. 

Danger  to  Live  Stock. — Those  using  the  method  described  in  this 
circular  are  warned  to  keep  stock  away  from  the  sprayed  morning- 
glory  patches.  Sheep  and  swine  are  very  fond  of  the  weed.  Forage 
plants,  when  sprayed  with  arsenicals,  seem  to  be  especially  attractive 
to  live  stock.  Cattle,  horses,  and  even  poultry  have  been  poisoned 
by  eating  Johnson  grass  which  had  been  sprayed  with  an  arsenical 
herbicide. 

Arsenic  Carried  by  Smoke. — "When  a  rank  growth  of  vegetation 
has  been  destroyed  with  a  heavy  arsenical  application,  considerable 
caution  must  be  used,  if  it  is  desired  to  burn  the  brush.  The  arsenic 
would  be  very  readily  volatilized  in  this  manner  and  would  be  carried 
in  the  smoke.  It  is  thought  that  a  poisonous  dose  of  arsenic  could 
be  easily  inhaled  in  this  way. 

Danger  to  Crops. — The  action  of  sodium  arsenite  is  more  severe 
on  broad-leafed  plants  than  on  grasses,  although  it  is  a  violent  poison 
to  practically  all  plants. 

Effect  on  the  Soil. — The  experiment  station  is  observing  the  effect 
of  arsenic  and  other  chemicals  on  the  soil.  Arsenic  is  accumulated 
in  the  top  layer  of  the  soil  and  is  not  easily  washed  out  by  rains,  so 
that  it  should  be  sparingly  used  on  agricultural  land,  and  only  by 
the  method  previously  described. 


Notwithstanding  its  poisonous  nature,  however,  arsenic  may  prove 
a  valuable  aid  to  the  farmers  of  the  state  in  the  control  of  some  of 
the  most  troublesome  weeds,  if  used  with  discretion. 

TREATMENT  TO  BE  USED  IN  CASE  OF  ARSENICAL  POISONING 

A  request  was  made  of  the  California  State  Board  of  Pharmacy 
to  recommend  the  most  approved  procedure  in  case  of  arsenical  poison- 
ing. Mr.  Louis  Zeh,  Secretary  of  the  Board,  has  kindly  furnished 
the  following: 

First  Aid. — The  first  thing  to  be  done  in  case  the  fluid  should  be  taken  by 
mistake  is  to  mix  two  teaspoonfuls  of  mustard  with  a  teaspoonful  of  salt  in  a 
cupful  of  water,  and  take  the  whole  at  one  draught.  If  vomiting  is  not  pro- 
duced in  ten  minutes,  repeat  the  dose,  and  follow  with  two  or  three  cupfuls  of 
warm  water  to  promote  vomiting;  then  give  the  antidote. 

Antidote. — The  antidote  to  be  used  in  case  of  poisoning  is  the  official  antidote 
for  arsenic  in  the  U.  S.  Pharmacopoeia.  This  may  be  made  as  follows:  Take 
two  bottles,  each  holding  a  quart;  place  in  one  of  them  one  hundred  and  fifty 
grains  (150)  of  magnesium  oxide,  and  fill'  it  two-thirds  full  with  water.  Into 
the  other  pour  o^e  and  a  third  ounces  of  the  solution  of  tersulphate  of  iron  U.  S.  P. 
and  fill  the  bottle  one-quarter  full  with  water.  When  the  antidote  is  to  be  used, 
shake  the  bottle  containing  the  magnesia  till  the  contents  are  suspended  in  the 
water;  then  add  the  contents  of  the  bottle  containing  the  solution  of  iron  to  the 
bottle  containing  the  magnesia  and  shake  well.  Give  half  a  tumbler  of  this 
mixture  for  a  dose.  After  remaining  in  the  stomach  about  five  minutes  it 
should  be  removed  by  vomiting  or  by  using  the  stomach  pump.  This  treatment 
should  be  repeated  three  or  four  times,  leaving  in  the  stomach  one-half  of  the 
last  dose. 

Precautions. — The  hands  should  be  protected  with  rubber  gloves  or  smeared 
with  lanolin  (wool  fat),  or  some  other  adhesive  grease,  to  prevent  absorption  of 
the  liquid  which  produces  poisonous  effects  if  applied  to  skin  equally  as  if  taken 
internally. 

The  face  should  be  greased  to  protect  it  as  well  as  the  hands.  To  protect  the 
eyes  goggles  should  be  worn. 

Treatment  of  External  Poisoning.— -If  the  liquid  comes  in  contact  with  open 
wounds  or  sores,  they  should  be  washed  with  water  and  soap,  rinsed  with  clean 
water,  and  the  antidote  applied.  Let  this  remain  on  the  hands  half  an  hour, 
and  then  remove  with  clean  water. 

If  any  of  the  liquid  should  get  into  the  eyes,  they  should  be  washed  with 
water,  and  a  bland  oil,  like  sweet  almond,  olive,  cotton  seed,  or  salad  oil,  put  into 
the  eyes.      Afterwards  bathe  the  eyes  with  a  warm  solution  of  boric  acid. 

Further  Treatment. — The  antidote  is  a  chemical  antidote  and  forms  a  less 
soluble  compound  with  the  arsenic,  but  should  always  be  removed  as  it  would 
eventually  be  absorbed  and  produce  poisoning.  Mucilaginous  drinks  should  be 
freely  taken  to  relieve  the  intense  thirst  and  burning  produced  by  the  arsenic. 

The  subsequent  treatment  should  be  left  to  a  physician  who  should  be  called 
immediately. 


STATION  PUBLICATIONS   AVAILABLE   FOR  FREE   DISTRIBUTION 


REPORTS 

1897.     Resistant  Vines,   their  Selection,  Adaptation,   and  Grafting.     Appendix  to  Viticultural 
Report  for  1896. 

1902.  Report  of  the  Agricultural  Experiment   Station  for   1898-1901. 

1903.  Report  of  the  Agricultural   Experiment   Station  for   1901-03. 

1904.  Twenty-second  Report  of  the  Agricultural  Experiment  Station  for    1903-04. 

1914.  Report  of  the  College  of  Agriculture  and  the  Agricultural  Experiment  Station,   July, 

1913-June,   1914. 

1915.  Report  of  the  College  of  Agriculture  and  the  Agricultural  Experiment   Station,   July, 

1914-June,    1915. 

1916.  Report  of  the  College  of  Agriculture   and  the  Agricultural   Experiment   Station,    July, 

1915-June,    1916. 

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138. 
139. 


140. 

111. 


Enological  Investigations. 

Vine  Pruning  in  California,  Part  I. 

Humus  in  California  Soils. 

Utilization  of  Waste  Oranges. 

Vine  Pruning  in  California,  Part  II. 

The  Economic  Value  of  Pacific  Coast 

Kelps. 
Stock-Poisoning  Plants  of  California. 
The  Loquat. 
Utilization  of  the  Nitrogen  and  Organic 

Matter   in    Septic    and    Imhoff   Tank 

Sludges. 
Deterioration  of  Lumber. 
Irrigation   and   Soil   Conditions  in  the 

Sierra  Nevada  Foothills,  California. 
The  Citricola   Scale. 
New  Dosage  Tables. 
Melaxuma    of    the    Walnut,     "Juglans 

regia." 
Citrus   Diseases   of  Florida   and   Cuba 

Compared  with  Those  of  California. 
Size  Grade  for  Ripe  Olives. 
The  Calibration  of  the  Leakage  Meter. 
Cottony  Rot  of  Lemons  in   California. 
A  Spotting  of  Citrus  Fruits  Due  to  the 

Action  of  Oil  Liberated  from  the  Rind. 


No. 

267.  Experiments  with  Stocks  for  Citrus. 

268.  Growing  and  Grafting  Olive  Seedlings. 

270.  A  Comparison  of  Annual  Cropping,  Bi- 

ennial Cropping,  and  Green  Manures 
on  the  Yield  of  Wheat. 

271.  Feeding  Dairy  Calves  in  California. 

272.  Commercial  Fertilizers. 

273.  Preliminary  Report  on  Kearney  Vine- 

yard Experimental  Drain. 

274.  The  Common  Honey  Bee  as  an  Agent 

in   Prune   Pollination. 

275.  The  Cultivation  of  Belladonna  in  Cali- 

fornia. 

276.  The  Pomegranate. 

277.  Sudan  Grass. 

278.  Grain   Sorghums. 

279.  Irrigation  of  Rice  in  California. 

280.  Irrigation  of  Alfalfa  in  the  Sacramento 

Valley. 

281.  Control  of  the  Pocket  Gophers  in  Cali- 

fornia. 

282.  Trials  with  California  Silage  Crops  for 

Dairy  Cows. 

283.  The  Olive  Insects  of  California. 

284.  Irrigation  of  Alfalfa  in  Imperial  Valley. 

285.  The  Milch  Goat  in  California. 


The  Common  Ground  Squirrels  of 
California. 

Spraving  Walnut  Trees  for  Blight  and 
Aphis  Control. 

Grape  Juice. 

Community  or  Local  Extension  Work 
by  the  High  School  Agricultural  De- 
partment. 

Correspondence  Courses  in  Agriculture. 

Increasing  the  Dutv  of  Water. 

Grafting  Vinifera  Vinevards. 

The  Selection  and  Cost  of  a  Small 
Pumping  Plant. 

The  County  Farm  Bureau. 

Some  Things  the  Prospective  Settler 
Should  Know. 

Alfalfa  Silage  for  Fattening  Steers. 

Spraying  for  the  Grape  Leaf  Hopper. 

House  Fumigation. 

Insecticide  Formulas. 

The  Control  of  Citrus  Insects. 

Cabbage  Growing  in  California. 

Spraying  for  Control  of  Walnut  Aphis. 

When  to  Vaccinate  against  Hog  Cholera. 

Countv  Farm   Adviser. 

Control  of  Raisin   Insects. 

Official  Tests  of  Dairy  Cows. 

Meiilotus  Indica. 

Wood  Decay  in  Orchard  Trees. 

The   Silo  in   California  Agriculture. 

The  Generation  of  H^drocvanic  Acid 
Gas  in  Fumigation  by  Portable  Ma- 
chines. 

The  Practical  Application  of  Tmnroved 
Methods  of  Fermentation  in  Califor- 
nia Wineries  during  1913  and  1914. 

Standard  Tnseet icides  and  Fungicides 
versus  Secret  Preparations. 


CIRCULARS 

No. 
142. 


Practical  and  Inexpensive  Poultry  Ap- 
pliances. 

143.  Control   of    Grasshoppers    in    Imperial 

Valley. 

144.  Oidium  or  Powdery  Mildew  of  the  Vine. 

145.  Suggestions  to  Poultrymen  concerning 

Chicken  Pox. 

146.  Jellies    and    Marmalades    from    Citrus 

Fruits. 

147.  Tomato   Growing  in  California. 

148.  "Lungworms." 

150.  Round  Worms  in  Poultry. 

151.  Feeding  and  Management  of  Hogs. 

152.  Some  Observations  on  the  Bulk  Hand- 

ling of  Grain  in  California. 

153.  Announcement  of  the  California   State 

Dairv  Cow  Competition,    1916-18. 

154.  Irrigation   Practice  in   Growing   Small 

Fruits  in  California. 

155.  Bovine  Tuberculosis. 

156.  How  to  Operate  an  Incubator. 

157.  Control  of  the  Pear  Scab. 

158.  Home  and  Farm  Canning. 

159.  Agriculture  in   the   Imperial  Valley. 

160.  Lettuce    Growing:   in    California. 

161.  Potatoes  in   California. 

162.  White    Diarrhoea    and    Coccidiosis    of 

Chicks. 

163.  Fundamentals  Affecting  the  Food  Sup- 

ply of  the  United   States. 

164.  Small  Fruit  Culture  in  California. 

165.  Fundamentals    of    Sugar    Beet    under 

California  Conditions. 

166.  The  County  Farm  Bureau. 

167.  Feeding  Stuffs  of  Minor  Importance. 

168.  Spraying  for  the  Control  of  Wild  Morn- 

ing-Glory within  the  Fog  Belt. 


